Halothioacyl fluorides and polymers thereof



United States Patent Ofifice 3,069,395 Patented Dec. 18, 1962 3,069,395 HALOTHIOACYL FLUORIDES AND POLYMERS THEREOF William J. Middleton, Claymont, Del., assignor to E. I.

du Pont de Nemours and Company, Wilmington, Del.,

a corporation of Delaware No Drawing. Filed Feb. 9. 195 9, Ser. No. 791,859 19 Claims. (Cl. 260-79) This invention relates to polymeric materials and their preparation, and more particularly to organic polymers containing both sulfur and fluorine.

Many varieties of polymers are known. Some have achieved commercial success in various applications, including such uses as films, fibers, coating compositions, adhesives, plastics, and the like. While the known polymers do have a diversity of properties or characteristics which result from particular structural composition and molecular weight, new types of polymers are continuously being sought.

One of the objects of this invention is to provide a new type of polymer. Another object is to provide a new class of polymers having novel structural units and which possess valuable properties and methods for preparing them. Other objects will become apparent hereinafter.

These and other objects of this invention are obtained by providing polymers of a-fluorothioacyl fluorides, including their copolymers with other copolymerizable monomers.

A preferred group of the polymers of this invention are polymers of iz-fiuorothioacyl fluorides wherein any other substituent besides a fluorine on the m-carbon, i.e., the carbon adjacent to the group, is hydrogen, halogen, hydrocarbon or halogenated hydrocarbon. These preferred polymers have recurring structural units of the formula wherein X and Y are hydrogen, halogen (fluorine, ch1o-. rine, bromine or iodine), monovalent hydrocarbon or halogenated monovalent hydrocarbon radicals, and especially hydrocarbon or halogenated hydrocarbon radicals having a 1-6 carbon atoms. group of polymers are the polymers of perfluorothioacyl fluorides, i.e., of compounds of formula where R, represents a perfluorocarbon group.

The polymers of this invention range from sticky, semisolids to plastics, to solid elastomers, and are generally colorless when pure. Many are soluble in ethers, e.g., diethyl ether, and some particular polymers are also soluble in other organic solvents. Poly(trifluorothioacetyl fluoride) is insoluble in most common solvents. The polymers are generally capable of being pressed into selfsupporting films, some of which are elastomer-ic.

Monomeric tr ifluorothioacetyl fluorideis also a part-of this invention.

The polymers of this invention are prepared by polym-* erizing monomeric u-fluorothioacyl fluorides, preferably those having the formula An especially preferred wherein X and Y have the meanings specified above, or a mixture of such a monomer with one or more other copolymerizable monomers, in the presence of an ionic initiator or in the presence of ultraviolet light.

The polymerization in the presence of an ionic initiator is conveniently carried out at relatively low temperatures, e.g., at a temperature between 0 and 120 C. or lower, in the presence of a solvent such as an ether, e.g., diethyl ether or tetrahydrofuran, or a hydrocarbon, e.g., pentane, that remains liquid at the operating temperature that is being used. The preferred temperature range for carrying out the polymerization is between 50 and C. In this temperature range, diethyl ether is a particularly effective solvent. Under these conditions hard, solid polymers are obtained. The polymerization times required vary from about 1 hr. up to several days, e.g., 3-4 days, depending on the particular operating conditions and the particular a-fluorothioacyl fluoride being polymerized.

A wide variety of ionic initiators can be used in this process. Specific initiators that are operable include dimethylformamide, primary, secondary and tertiary amines, e.g., triethylamine, diisopropylamine, and aniline, triphenylphosphine, nitrosodimethylamine, quaternary ammonium chlorides having no hydrogen on the quaternary ammonium nitrogen, e.g., tetraethyl quaternary ammonium chloride, quaternary ammonium methoxide, and the like. Dimethyltorrnamide is a particularly effective initiator in this reaction. The ionic initiators can be employed in concentrations ranging from about 0.2% to 20% of the weight of the monomer being polymerized.

The polymerization in the presence of ultraviolet light as the initiator is conveniently carried out in the presence of inert solvents such as highly halogenated hydrocarbons, e.g., dichlorodifluoromethane. Any convenient source of ultraviolet light can be used. For example, any of the commercially available lamps that are relatively high in ultraviolet output are suitable. Generally speaking, mercury vapor arc lamps are preferred since they provide ia relatively intense source of ultraviolet light. Many lamps of this type are available and they include low and high-pressure lamps with various types of en velopes. The most preferred are those with quartz envelopes since such envelopes permit the highest percent transmission of ultraviolet light.

The temperature and pressure at which the polymerization in the presence of ultraviolet light is carried out are. not critical. It is convenient to use room temperature and atmospheric pressure but lower or higher temperatures and lower or higher pressures can be used if de* sired. It is convenient to carry out the polymerization at the boiling point of the solvent being used. At ordinary temperatures and pressures, the polymerizationis substantially complete in about 1 hour. However, the polymerization can be continued for several hours, e.g., 6-8 hours, or even more, if desired.

As indicated above, the polymers of this invention in-. clude copolymers of the a-fluorothioacyl fluorides with one or more other u-fluorothioacyl fluorides, and with other copolymerizable monomers which contain substantial proportions, i.e., at least 5 mole percent of the wfluorothioacyl fluoride. Examples of typical monomers which can be copolymerized with the u-fluorothioacyl fluorides include ethylenically unsaturated compounds that undergo vinyl-type polymerization, e.g., propylene, and thiocarbonyl compounds, e.g., thiocarbonyl fluoride, thiocarbonyl fluoride chloride, and fluorinated thioketones. These copolymers can be prepared by subjecting mixtures of the a-fluorothioacyl fluoride with one or more of the other polymerizable monomers in the desired proportions to the polymerizing conditions described in the preceding paragraphs.

The polymers of e-fiuorothioacyl fluorides can be iso- 3 lated from the polymerization systems in various ways. In one method, the solvent is removed by evaporation or distillation and the residue obtained can be washed with water or other inert solvent if desired. In another method,

the solution of the polymer is poured into a non-solvent, e.g.-, petroleum ether, to precipitate the polymer, or a nonsolvent can be added to the polymerization solution to precipitate the polymer. The precipitated polymer can where R is a fiuoroalkyl radical and X is hydrogen, chloride or fluorine with sulfur or phosphorus pentasulfide at a temperature above 400 0, preferably at a temperature at which the sulfur or phosphorus pent'asulfide is molten. (See Examples IXXI.)

The polymers of this invention and their preparation from a-fluorothioacyl fluorides, as well as the preparation of the monomeric fluorides, are illustrated in further detail by the following examples in which the proportions of ingredients are expressed in parts by weight unless otherwise specified.

EXAMPLE I "(11) Preparation of Chlorofluorothioacetyl Fluoride HOlOFCF2SH+NaF HClOFI3-F+NaHFa Eight parts of 2-hydro-2-chloroperfluoroethanethiol (prepared by the X-ray initiated addition of hydrogen sulfide to chlorotrifluoroethylene) is placed in a vessel equipped with a capillary nitrogen inlet tube extending to the bottom of the vessel. The top of the vessel is connected to a by 1' reaction tube, made of glass and packed with sodium fluoride pellets. The end of the glass tube is connected to a vaccum line through two traps cooled by solid carbon dioxide-acetone. A slow stream of nitrogen is passed through the capillary and the system is evacuated to about 170 mm. of mercury pressure. A period of about 0.5 hour is required to completely volatilize the thiol. There is obtained in the cold trap 5.2 parts (corresponding to a 75% yield) of a liquid which is distilled through a small column to give 4.3 parts (62.5% of theory) of chlorofluorothioacetyl fluoride. This product is a yellow liquid, boiling at 57 C.

: A nalysis.Calcd for C HCIF S: Cl, 27.2%; F, 29.1%; S, 24.5%. Found: Cl, 27.3%; F, 29.5%; S, 24.6%.

, The nuclear magnetic resonance and infrared spectra obtained on this product also confirm the structure of the product;

(B) Polymerization of Chlorofluorathioacetyl Fluoride Three-tenths part of chlorofluorothioacetyl fluoride is mixed with 1.5 parts of dry diethyl ether and the result. ing solution is cooled in a bath of solid carbon dioxideacetone. One drop of purified dimethylformamide is added and the mixture is stirred. After about 0.5 hour, two additional drops of dimethylformamide are added and the solution is stirred again. It becomes noticeably more viscous after the second stirring. After standing in the solid carbon dioxide-acetone bath overnight, the mixture is a virtually colorless, viscous solution. The polymer is isolated by pouring the ether solution into petroleum ether. The precipitated polymer is removed, dissolved again in diethyl ether, and the ether solution is allowed to evaporate on a glass surface. There is obfluorothioacetyl fluoride) which is somewhat elastic.

EXAMPLE II A solution of 4.78 parts of chlorofluorothioacetyl fluoride (prepared as described in Example I) and 20 parts of dichlorodifluoromethane in a quartz tube fitted with a reflux condenser cooled by a mixture of solid carbon dioxide and acetone is irradiated with a spiral shaped quartz, low pressure, mercury resonance lamp (approximately 10 watts) for a period of 2 hours. At the end of this time, a white solid polymer has formed as a precipitate, amounting to 4.4 parts. This white polymer is warmed (at 55 C.) under vacuum (0.1-1.0 mm. mercury) overnight.

Analysis.Calcd for (C HC1F S),,: Cl, 27.2%; F, 29.1%; S, 24.5%. Found: Cl, 26.7%; F, 29.7%; S, 24.5

i This polymer of chlorofluorothioacetyl fluoride is pressed at 5060 C. into (.lms which possess some elas-' ticity. When pressed at 150 C. hard, clear colorless films are obtained.

EXAMPLE III I (A) Preparation of Difluorothioacetyl Fluoride with a condenser cooled by solid carbon dioxide and ace tone.' There is obtained 5.0 parts of difiuorothioacetyl fluoride as a clear, yellow liquid boiling at 14-16" C. The

nuclear magnetic resonance pattern obtained on this product is consistent with the structure written above.

(B) Polymerization of Difluorothioacelyl Fluoride A solution of 1 part of difluorothioacetyl fluoride in 2.2 parts of dry diethyl ether is cooled in a bath of solid carbon dioxide and acetone. One drop of a 10% solution of dimethylformamide in dry ether is added. The mixture is agitated for a few seconds and then allowed to stand at 76 C. overnight. At the end of this period the mixture is completely solidified and is colorless. It is allowed to warm to room temperature where it becomes fluid, and is then poured into 300 parts of water. After the ether is evaporated there remains 0.82 part of white solid poly(difluorothioacetyl fluoride). This polymer is swelled by diethyl ether and is pressed at C. into tough, somewhat elastic films.

EXAMPLE IV A solution of 2 parts of difiuorothioace'tyl fluoride (prepared as described in Example III) and 25 parts of dichlorofluoromethane is irradiated with ultraviolet light as described in Example II for a period of 2 hours. At the end of. this time, the solution is distilled to remove the solvent and the poly(difluorothioacetyl fluoride) remaining is removed from the reactor by dissolving it in anhydrous ether. Evaporation of the ether from the resultingsolution upon a glass surface produces 1.58 parts of a colorless solid film of poly(difluorothioacetyl fluoride) which is elastic.

Analysis.-Calcd for (C HF S) S, 28.1%.v S, 28.2%.

Found:-

white and solidifies.

EXAMPLE v (A) Preparation of T rifluorothioacetyl Fluoride eorioripizs t (CFgOlF Sh-l-Iz A mixture of 150 parts of sulfur and 150 parts of pentafluoroethyliodide is heated for 12 hours at 250 C. and agitated in a reaction vessel capable of withstanding high pressure. The reaction vessel is then cooled and the volatile products are removed by distillation under vacuum. The distillate is shaken with mercury and then redistilled. There is obtained 72.7 parts of pentafluoroethyl disulfide boiling at 78-79" C. and having a refractory index, n of 1.3225.

A solution of 30.2 parts (0.1 mole) of pentafluoroethyl disulfide in 62 parts of 2,2,3,3,4,4,5,5-octafluoropentanethiol (made by reductive thiolation of 2,2,3,3,4,4,5,5-octafluoropentanal withhydrogen sulfide at about 200 C.) is irradiated with a low pressure mercury lamp for 4 days. A slow stream of nitrogen gas is passed through the reactionmixture during the irradiation and the effluent gases are condensed in a trap cooled by solid carbon dioxide and acetone. The condensate is distilled through a low temperature still andthere is obtained 9.1 parts of pentafluoroethanethiol boiling at 6 to 4 C. asavery pale liquid.

Six parts of this pentafluoroethanethiol is slowly vaporized in a stream of nitrogen and passed through a column packed with 50 parts of sodium fluoride pellets and connected to a trap cooled by solid carbon dioxide and acetone. The yellow condensate obtained in the trap is distilled through a low temperature still and there is obtained 5.0 parts of trifluorothioacetyl fluoride boiling at 19 to -18 C. as a bright yellow liquid. The product is identified by examination of its nuclear magnetic resonance spectrum.

.(B) Polymerization of T rifluorothioacetyl Fluoride A solution of 2 parts of trifluorothioacetyl fluoride in 7 parts of diethyl ether is cooled in a bath of solid carbon dioxide and acetone and 1 drop of dimethylformamide is added. The solution is allowed to remain in the cooling bath for 1 hour. An additional drop of dimethylformamide is added, whereupon the entire solution becomes The reaction mixture is allowed to warm to room temperature where it becomes fluid, and it is then poured into acetone. The polymerwhich precipitates is collected on a filter and is dried in a vacuum. There is obtained 2 parts of white rubbery poly(trifiuorothioacetyl fluoride) which is insoluble inacetone, diethyl ether, alcohol, pentane, benzene and other common solvents.

Analyst's.Cal cd for (C F S) C, 18.19%; F, 57.54%; S, 24.27%. Found: C, 18.21%; F, 57.31%; 5, 24.01%.

A rubbery film is pressed from the poly(trifluorothioacetyl fluoride) at 10,000 lb./sq. in. pressure at 65 C. The film has an elongation of about 800% with very logy recovery. The polymer decomposes slowly when heated at 95 C.

EXAMPLE VI (A) Preparation of Pentaflttorothiopropionyl Fluoride H(GF2)4CH2SH (cFsGFa z lz Fs FzcFzsH Pentafluorothiopropionyl fluoride is prepared in a manner similar to that described in Example V except that heptafluoropropyl disulfide is substituted for the pentafluoroethyl disulfide of that example.

(B) Polymerization of Pentafluorothiopropionyl Fluoride A solution of 2 parts of pentafluorothiopropionyl fluoride (B.P. approximately 9 C.) in 7 parts of diethyl ether is cooled in a bath of solid carbon dioxide and acetone and 2 drops of dry dimethylformamide is added. The ether solution is allowed to remain in the cold bath for three hours and is then allowed to warm to room temper.- ature. Methyl alcohol is added to the solution and the polymer that separates is collected and dried. There is obtained 1.3 parts of a very light pink, sticky, semi-solid poly(pentafluorothiopropionyl fluoride). This polymer is soluble in diethyl ether but is insoluble in alcohol.

Atmlysis.Calcd for (C F S) C, 19.79%; F, 62.61%, S, 17.61%. Found: C, 19.57%; F, 62.41%; S, 17.42%.

EXAMPLE VII (A) Preparation of Chlorodifluorothiottcetyl Fluoride C H SH (CICFzCFzQ); T C1CF CF SH+OaHsSSC H ethanetln'ol boiling at 33 C. as a pale yellow liquid.

The 2-chlorotetrafluoroethanethiol is dehydrofiuorinated ,by sodium fluoride pellets as described in Example I and there is obtained ehlorodifiuorothioacetyl fluoride boiling at 17-19" C. as a deep yellow liquid.

(B) Polymerization of Chlorodifluorothioacetyl Fluoride A solution of 2 parts of chlorodifluoroth-ioacetyl fluoride in 7 parts of dry diethyl other is cooled to C. and 1 drop of a 50% solution of dimethylfo-rmamidein diethyl ether is added. The solution is agitated and is then allowed to remain at 80 C. for 2 hours. The solution is warmed to room temperature and the solvent is evaporated by a stream of nitrogen. A film of robbery polymer is left. The poly(chlorodifiuoro thioacetyl fluoride) is collected, washed with acetone and dried under vacuum for 16 hours. The resulting polymer is hard and crystalline but not brittle. It becomes rubbery when heated above 50 C. and sticky at temperatures above C.

Attalysis.Calc"d for (C ClF S) C, 16.17%; Cl, 23.87%; F, 38.24%; S, 21.58%. Found: C, 16.46%; Cl, 24.06%; F, 38.24%; S, 21.51%.

EXAMPLE VIII (A) Preparation 0) T rifluorotliioacetyl Fluoride s ass i (0 E 0 FH) I-Ig 2 CF 0 F A 300-ml. three-necked flask fitted with a thermocouple, ertical glass tube 1 inch in diameter and 18 inches long to which is aflixed a trap cooled by acetone-solid carbon dioxide, and means for adding solid reactants in a nitrogen atmosphere is charged with 100 g. of phosphorus pentasulfide. The fiask is flushed with nitrogen and heated to cause the phosphorus pentasulfide to reflux (520 C.) a few inches up'the glass tube. To the refluxing pentasulfide is added in small portions during 15 minutes 27.0 g. of bis(1-hydroperfiuroethyl)rnercury. The reaction products collected in the cold trap are distilled and there is obtained 1 ml. of trifiuorothioacetyl fluoride, which is identified by its nuclear magnetic resonance spectrum.

(B) Copolymerization of Trifluorothioacetyl Fluoride With Thiocarbonyl Fluoride In a polymerization vessel cooled in a solid carbon dioxide/acetone mixture and blanketed with helium are placed 14 parts of anhydrous ether, 10.5 parts of thiocarbonyl fluoride and 3 parts of trifluo-rothioacetyl fluoride. To the resulting solution is added a solution of about 0.1 part of N-methylmorpholine in 3.5 parts of anhydrous ether. Polymerization begins almost immediately. After 5 hours, much solid polymer has precipitated and the reaction mixture is poured into hot hydrochloric acid (cone. HCl diluted with an equal volume of water). The polymer is washed with water and with acetone and is dried in vacuo at 60 C. It amounts to 9.7 parts.

The crude polymer is dissolved in 595 parts of chloroform (no residue) and is precipitated by adding 40 parts of methanol to the chloroform solution. The filtered and dried (60 C., in vacuo) polymer amounts to 8.8 parts. The polymer can be pressed to a limp, opaque film at 150 C. and 10,000 lbs. ram pressure. The polymer slowly crystallizes on standing at room temperature. It exhibits an inherent viscosity of 1.19, measured in 0.1% chloroform solution. Analyses indicate a CF S/CF CSF ratio of 88:12. The ratio of monomers charged is 85: 15.

Analysis.Calcd for[CF S] [CF CSF] C, 15.3%; F, 48.2%; S, 36.5%. Found: C, 15.36%; F, 48.78%; S, 36.53%.

EXAMPLE IX (A) Preparation of T rifluorothioacetyl Fluoride (CFsCFHhHg 2 CF i ZF Following the procedure of Example VIII 33.0 g. of bis( l-hydroperfiuoroethyl) mercury is added in increments over a period of 20 minutes to 100 g. of refluxing sulfur (445 C.). There is obtained in the cold trap 7.0 ml. of crude product which on distillation yields 9.0 g. (56% of theory) of trifluorothioacetyl fluoride.

(B) Copolymerizativn of Trifluorothioacetyl Fluoride With T hiocarbonyl Fluoride In a polymerization vessel cooled in a solid carbon dioxide/acetone mixture and blanketed with helium are placed 7 parts of anhydrous ether, 4.5 parts of thiocarbonyl fluoride and 4.5 parts of trifluorothioacetyl fluoride. To the resulting solution is added a solution of about 0.1 part of tetraisopropyl titanate in 3.5 parts of anhydrous ether. The polymerization is run five hours at 80" C. and the reaction mixture is then poured into methanol. The polymer is separated by decantation, washed with methanol and dried in vacuo at 60 C. The polymer is dissolved in 248 parts of chloroform (0.8 part residue) and is then precipitated with 60 parts of methanol. After drying at 60 C. in vacuo it amounts to 5.1 parts. The polymer can be pressed to a limp, opaque film at 0 C. and 10,000 lbs. ram pressure. The polymer exhibits an inherent viscosity of 1.01 (measured in 0.1% chloroform solution) and does not crystallize at 28 C. Analyses show it to contain a CF S/CF CSF ratio of about 60:40. The ratio of monomers charged is 62:38.

Analysis.Calcd for '(CF S) (CF CFS) C, 16.5%; S, 31.4%; F, 52.1%. Found: C, 16.20%; S, 31.84%; F, 50.14%.

EXAMPLE X (A) Preparation of Trifluorozhioacetyl Fluoride (CF CFCDgHg 2 CFS F In a 500 ml. round-bottom flask equipped with a means for adding solid mercurial in a nitrogen atmosphere, a nitrogen inlet tube, and an air condenser leading to a trap cooled by solid carbon dioxide is placed 100 g. of powdered sulfur. The sulfur is then heated to 480- 500 C. (vigorous refluxing) and 50 g. of bis(1-chloroperfluoroethyl)mercury is added in 1-2 g. increments over a period of 1 hour. The liquid product obtained in the cold trap (19 ml. at C.) is transferred to a low temperature still. On distillation there is obtained as a center cut 18 g. of pure trifluorothioacetyl fluoride, B.P. 22 C. The yield of crude acid fluoride is 92%, that of the purified material is 60%.

(B) Copolymerization of Trifluorothioacetyl Fluoride With T hiocarbonyl Fluoride and Chlorofluornthioacetyl Fluoride In a polymerization vessel cooled in a solid carbon dioxide/acetone bath and blanketed with nitrogen are placed 14 parts of anhydrous ether, 6 parts of thiocar bonyl fluoride, 2.3 parts of CF CSF and 0.8 part of chlorofluorothioacetyl fluoride. To the resulting solution is added a solution of about 0.05 part of N-methylmorpholine in 3.5 parts of ether. Polymerization begins immediately. After 5 hours the reaction mixture is poured into methanol, the methanol is decanted, the residue is washed with methanol and dried in air at room temperature. It amounts to 5.4 parts. The polymer is dissolved in 447 parts of chloroform (no residue) and is precipitated with 60 parts of methanol. After drying in vacuo at 60 C. it amounts to 5.0 parts. The polymer can be pressed to a limp, semi-elastic, opaque film at C. and 10,000 lbs. ram pressure, has an inherent viscosity of 0.82 (0.1% solution in chloroform) and is shown by elemental analysis to contain all three comonomers. Analysis found: S, 34.47%; Cl, 1.11%.

EXAMPLE XI (.4) Preparation of Pentafluorothi0-3-Butenoyl Fluoride Forty parts of sulfur is placed in the bottom of an upright U-tube 1" in diameter and 12" high. One end of the U-tube is fitted with a dropping funnel and the other end is connected to a trap cooled by a mixture of acetone and solid carbon dioxide. A slow stream of nitrogen is passed through the tube and the sulfur is heated until its vapor refluxes about 4" up the arms of the tube. 4,4-diiodoperfluoro-l-butene (6.2 parts) is added dropwise over a period of 30 minutes through the dropping funnel. The liquid that condenses in the cold trap is distilled at atmospheric pressure. There is obtained 2.04 parts of a bright yellow liquid boiling at 45- 46 C., which is perfluorothio-3-butenoyl fluoride.

Analysis.-Calcd for C F S: C, 24.75%; F, 58.73%; S, 16.52%. Found: C, 24.63%; F, 58.58%; S, 16.82%.

(B) Polymerization of Pentafluorothio-3-Butenoyl Fluoride A sample of pentafluorothio-3butenoyl fluoride is sealed in a glass tube and stored at room temperature for two weeks. At the end of this period, the sample has become solid. The tube is opened and the solid polymer of pentafluorothio-3butenoyl fluoride is removed. It is a rubbery yellow solid that maintains its rubbery characteristics at temperatures up to its decomposition point, which is 240 C. The polymer is pressed at 225 C. under 15,000 lbs/sq. in. to a clear film which is tough and resistant to solvents. The polymer is insoluble in acetone, ether, ethyl alcohol, pentane, benzene, dimethylformamide, nitric acid, and 10% aqueous sodium hydroxide.

Analysis.Calcd for (C F S) C, 24.75%; S, 16.52%. Found: C, 24.55%; S, 16.40%.

EXAMPLE XII Cop lymerization of Trifluorothioacetyl Fluoride With Propylene A mixture of 4.2 parts (0.1 mole) of propylene and 13.2 parts (0.1 mole) of trifluorothioacetyl fluoride is sealed in a glass tube and kept at room temperature (about 25 C.) for 3 days. The tube is cooled to 78 C., opened, and then allowed to warm to room temperature. A white, rubbery polymericmaterial remains in the tube. A colorless, clear elastomeric film is pressed from it at 60 C. and 10,000 lbs/sq. in. Elemental analyses indicate the copolymer contains 11% propylene and 89% trifluorothioacetyl fluoride.

Analysis.-Calcd for 89% C F S+1l% 'C H F, 51.21%; S, 21.89%. Found: F, 51.22%; S, 21.60%.

The examples have illustrated the polymers of this invention, including both ot-fluorothioacyl fluoride homopolymers and copolymers. The invention includes any a-fluorothioacyl fluoride polymer having recurring structural units,

wherein X and Y represent hydrogen, halogen, monovalent hydrocarbon or halogenated monovalent hydrocarbon radicals. Thus, in addition to specific polymers illustrated by the examples, other specific polymers that can be mentioned include polymers of monoflnorothioacetyl fluoride, pentafluorothio-3-butenoyl fluoride, and 2,2-difluorothiopropiony1 fluoride.

The polymers of a-fluorothioacyl fluorides of this invention, including copolymers with other copolymerizable monomers, are useful for a wide variety of purposes in view of the wide range of properties they possess, i.e., varying from sticky, semi-solids, to plastics, to elastomeric solids. The semi-solid, sticky polymers are useful as adhesives. Since the solid polymers flow at temperatures up to about 150 C., they are particularly useful for use as molding compositions. The solid polymers are also useful when shaped into self-supporting films, which range from opaque to transparent films, by either solvent casting or pressing. The films prepared from the solid polymers having elastomeric properties can be used in those applications where films and sheets having elastomeric properties are ordinarily used. Likewise, the films prepared from the plastic polymers can be used in those applications where plastic films and sheets are ordinarily used. Polymeric trifluorothioacetyl fluoride is especially useful as an elastomer.

The a-fluorothioacyl polymers are also useful as electrical insulation for flexible metal objects, e.g., for wire and plates. As an illustration, copper wire is heated in a flame and then drawn back and forth between a folded film of difluorothioacetyl fluoride polymer. When the wire is cooled the previously heated area is coated with the polymer. This polymer coating does not break off when the wire is bent sharply several (4-5) times. Thus, these polymers are useful as insulating coatings on wires.

In addition to its utility in the preparation of polymers, trifluorothioacetyl fluoride is useful as a fumigant. It is particularly effective against houseflies as shown by the following test. The introduction of 300 mg. of trifluorothioacetyl fluoride into a closed container of about 450 cc. capacity containing 50 adult houseflies (3-4 days old) and a 2% sugar solution as a food source caused a 100% knockdown of the flies before the fumigant was completely introduced. One hour after the fumigant was introduced, the lid was removed from the container in order to evacuate the free gas and at the end of a 20-hour count all the flies were dead. In a control test carried out in the same way with the same number of flies but with the single exception that no fumigant was used, no dead flies were observed.

The foregoing detailed description has been given for clearness of understanding only and no unnecessary limitations are to be understood therefrom. The invention is not limited to the exact details described, for obvious modifications will occur to those skilled in the art.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Polymers having the sole recurring unit wherein X and Y are selected from the group consisting of hydrogen, halogen, alkyl of 1-6 carbon atoms and halogenated alkyl of 1-6 carbon atoms.

2. Polymers having as the sole recurring unit wherein X and Y are perfluoroalkyl of 1-6 carbon atoms. 3. Copolymers wherein at least 5% of the number of recurring units are wherein X and Y are as defined in claim 1, and the remaining recurring units are provided by polymerizable ethylenically unsaturated compounds free of thiocarbonyl groups.

4. Pentafluorothio-3-butenoyl fluoride.

5. Polymers of claim 1 in the form of pressed shaped structures.

6. Polymers of claim 1 in the form of self-supporting films.

7. Poly(trifluorothioacetyl fluoride).

8. Poly(pentafluorothiopropionyl fluoride).

9. Poly(chlorodifluorothioacetyl fluoride).

11. Process for preparing polymers which comprises cooling a monomer selected from the class consisting of u-fluorothioacyl fluorides and mixtures thereof with at least one other copolymerizable monomer tselected from polymerizable 1 ethylenically unsaturated compounds free of thiocarbonyl groups to a temperature of from 0 to about -l20 C., and effecting contact between said cooled monomer and an ionic initiator, said initiator being present in amount of from 0.2% to 20% of the monomer being polymerized.

12. Process for preparing polymers described in claim 1 which comprises subjecting a monomeric Ot-flllOl'OthlO acyl fluoride to a temperature of from 0 C. to about C. in the presence of an ionic initiator, said initiator being present in an amount of from 0.2% to 20% of the monomeric ot-fluorothioacyl fluoride.

13. The process of claim 11 wherein the polymerization is effected in the presence of an inert solvent which is liquid at the operating temperature.

14. The process of claim 11 wherein the polymerization is effected in the presence of dimethylforrnamide and diethyl ether, said dimethylformamide being present in an amount of from 0.2% to 20% of the monomer being polymerized.

15. Process for polymerizing pentafluorothio-3-butenoyl fluoride which comprises storing said fluoride in a closed container under autogenous pressure for a time suflicient to effect substantial homopolymerization.

16. Process which comprises mixing substantially equal molecular quantities of propylene and trifluorothioacetyl fluoride and storing said mixture in a closed container 3,069,895 "111 12 under autogenous pressure for a period sufficient to efiect References Cited in the file of this patent substantial copolymerization. 17. Polymers of claim 7 in the form of self-supporting fil 2,480,467 Haworth et a1 Aug. 30, 1949 18. Polymers of claim 8"in the form of self-supporting 5 TH REFERENCES films.

Lovelace et al.: Aliphatic Fluorine Compounds, Rein l9. Polmyers of claim 9 in the form of self-supporting h 01 d Publishing company New York, 1958, page 337. 

1. POLYMERS HAVING THE SOLE RECURRING UNIT 